In 2011, Barath Raghavan and Justin Ma of ICSI and University of California, Berkeley, took on the task of estimating the amount of electricity the Internet requires. They decided to take into account the energy we use to create the Internet itself. That includes all the power needed to build computers, network connections, cell-phone towers and other hardware. They called this embodied energy or "emergy."

Raghavan and Ma relied on general estimates for all their work and acknowledged in their report that their answer was not accurate. Their stated goal was to bring attention to the matter so that others might think on the issue more deeply. Their estimates included:

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750 million desktop computers

750 million laptop computers

1 billion smartphones

100 million servers

They also included other Internet infrastructure elements. They weighted each category of device with a minimum and maximum value to create a range of energy requirements because one computer might require less energy to produce and run than another. They also took into account the average life cycle of each piece of the infrastructure.

Ultimately, Raghavan and Ma estimated the Internet uses 84 to 143 gigawatts of electricity every year, which amounts to between 3.6 and 6.2 percent of all electricity worldwide. Taking emergy into account, the total comes up to 170 to 307 gigawatts. That's a lot of energy, but amounts to just under two percent of worldwide energy consumption.